Report ITU-R SA.2426-0 (09/2018) Technical characteristics for telemetry, tracking and command in the space operation service below 1 GHz for non-GSO satellites with short duration missions SA Series Space applications and meteorology ii Rep. ITU-R SA.2426-0 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Reports (Also available online at http://www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2018 ITU 2018 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rep. ITU-R SA.2426-0 1 REPORT ITU-R SA.2426-0 Technical characteristics for telemetry, tracking and command in the space operation service below 1 GHz for non-GSO satellites with short duration missions (2018) 1 Introduction This Report responds to invites 1 in Resolution 659 (WRC-15) described below and contains the technical characteristics for telemetry, tracking and command (TT&C) in the space operations service for non-GSO (NGSO) satellites with short duration missions. These characteristics are intended to inform further studies on the spectrum requirements of short duration missions (see Report ITU-R SA.2425-0) as well as sharing studies carried out in Report ITU-R SA.2427-0. Short duration missions are understood in this context to have a mission lifetime not exceeding more than three years. Examples of similar missions are described in Report ITU-R SA.2312, and descriptions of current regulatory practices relating to space network notification are contained in Report ITU-R SA.2348. It is understood that the number of missions of this category may increase. A maximum mission lifetime of three years is understood to be typical for these short duration missions. Resolves 1.1 of Resolution 4 (Rev.WRC-03) states that the period of validity “shall be limited to that for which the satellite network was designed”. Furthermore, according to resolves 1.2 of this Resolution, a notifying administration has to inform the Bureau more than three years before the expiry of the period of validity if it wishes to extend the period of validity. Therefore, for short duration mission satellites, such extension is not a possibility, and it should be noted that is in line with their typical lifetime. The term “short duration mission” used in Resolution 659 (WRC-15) refers to a mission having a limited period of validity of not more than typically three years. Therefore, the term “short duration mission” is not directly tied to the lifetime of the spacecraft. For example, a single spacecraft with a lifetime of less than typically three years, where the operator does not launch a replenishment or replacement spacecraft, is a short duration mission. However, in the case of a (or multiple) spacecraft with a lifetime of less than typically three years, where the operator launches a (or multiple) replenishment or replacement spacecraft(s) such that the operator has a persistent frequency assignments longer than typically three years, is not a short duration mission. Resolution 659 (WRC-15) calls to study the spectrum needs for telemetry, tracking and command in the space operation service below 1 GHz for NGSO satellites with short duration missions, to assess the suitability of existing allocations to the space operation service and, if necessary, to consider new allocations. Resolution 659 (WRC-15) invites ITU-R: 1 to study the spectrum requirements for telemetry, tracking and command in the space operation service for the growing number of non-GSO satellites with short duration missions, taking into account RR No. 1.23; 2 to assess the suitability of existing allocations to the space operation service in the frequency range below 1 GHz, taking into account recognizing a) and current use; 3 if studies of the current allocations to the space operations service indicate that requirements cannot be met under invites ITU-R 1 and 2, to conduct sharing and compatibility 2 Rep. ITU-R SA.2426-0 studies, and study mitigation techniques to protect the incumbent services, both in-band as well as in adjacent bands, in order to consider possible new allocations or an upgrade of the existing allocations to the space operation service within the frequency ranges 150.05-174 MHz and 400.15-420 MHz. 2 Technical and operational characteristics of non-GSO satellites with short duration missions The following Tables are applicable only to individual short duration NGSO spacecraft. 2.1 Orbital characteristics Most NGSO satellites with short duration missions are launched into low earth orbit (LEO). Table 1 provides typical orbital characteristics of these satellites. TABLE 1 Typical orbital characteristics of NGSO satellites with short duration missions RR Appendix 4 Parameter Value data element Apogee altitude A.4.b.4.d 300-1 000 km Perigee altitude A.4.b.4.e 300-1 000 km Angle of inclination of the orbital A.4.b.4.a 0-100 degrees plane with respect to the Earth’s equatorial plane 2.2 Technical characteristics specific to the space-to-Earth direction Report ITU-R SA.2312 provides a number of characteristics related to nanosatellites and picosatellites. Table 1 of Report ITU-R SA.2312 states a mission duration (which is directly linked to the period of validity) of typically less than three years, while Table 4 of the Report states typical RF parameters of bandwidth, antenna gain factors and transmission power. Table 2 below provides typical characteristics for NGSO satellite networks with short mission duration applicable to the space-to-Earth direction. The value for necessary bandwidth renders the values stated in Report ITU-R SA.2312 (which states less than 100 kHz) more precisely. The value in the Table is based on an analysis of currently filed systems that could be regarded as short duration missions. Moreover, it is in line with available transceivers for these systems, which typically employ data rates of not more than 9.6 kbit/s and a spectral efficiency of at least 0.5 bit/s/Hz. Since the link under discussion should only be used for TT&C and the amount of TT&C data for short duration missions is low, this value should also be suitable for future missions. Rep. ITU-R SA.2426-0 3 TABLE 2 Typical technical characteristics for the use of frequency bands below 1 GHz in the space-to-Earth direction Parameter RR Appendix 4 Typical values Typical values data element at VHF frequencies, at UHF frequencies, 30-300 MHz 300-1 000 MHz Necessary bandwidth C.7 ≤ 25 kHz ≤ 25 kHz Space station transmit power C.8.a.1 ≤ 1 W ≤ 1 W delivered to antenna Space station antenna gain B.3.a.1 ≤ 3 dBi ≤ 3 dBi Space station antenna pattern B.3.c.1 ND-SPACE ND-SPACE Space station/earth station N/A 1 dB 1 dB tracking antenna pointing loss Space station antenna type N/A Omnidirectional Omnidirectional Space station antenna C.6 Linear Linear polarization Space station emission mask description (e.g. −3 dB, N/A Refer to § 2.5 Refer to § 2.5 −20 dB, −60 dB, −80 dB) Earth station system noise temperature (including cable C.10.d.6 1 500 K 500 K loss, filter, etc.) Earth station antenna type N/A Yagi-Uda or Parabolic Yagi-Uda or Parabolic Earth station peak antenna 10-17 dBi; 10-17 dBi; C.10.d.3 gain typically 12 dBi typically 16 dBi Earth station antenna pattern C.10.d.5.a Rec. ITU-R F.699-7 Rec. ITU-R F.699-7 Earth station antenna 3 dB N/A 50 degrees 30 degrees beamwidth Earth station antenna N/A Circular Circular polarization Earth station emission mask description (e.g. −3 dB, N/A Refer to § 2.5 Refer to § 2.5 −20 dB, −60 dB, −80 dB) Earth station minimum N/A 5 degrees 5 degrees elevation angle C/N objective C.8.e.1 12 dB 12 dB Operational duty cycle during N/A up to 100% up to 100% earth station contact SOS Protection criteria N/A Rec. ITU-R SA.363-5 Rec. ITU-R SA.363-5 2.3 Technical characteristics specific to the Earth-to-space direction Table 3 provides typical characteristics for NGSO satellite networks with short mission duration applicable to the Earth-to-space direction.